Previous oil pressure transducers have utilized a two-part housing capturing a flexible diaphragm member therebetween. Typically, the diaphragm is movable in response to the pressure of the engine oil so as to operate warning switch means. The switch means are connected into a warning circuit so that when oil pressure falls below a desired minimum level, a warning light or the like is activated. The two-part housing is normally joined together with the aforementioned diaphragm therebetween by means of an edge rolled portion of one housing over the other housing in a mechanically deforming operation.
In addition to using an edge roll type of connection, retaining rings or annular members have been utilized to connect transducer housing portions together. This is also an effective means of joining the housings. However, in some applications, the radial space about the housings is quite limited and it is undesirable to utilize a retaining device which does not project outwardly from the housing. Accordingly, the present transducer incorporates annular split rings with portions which are expandable in the radial direction and interfit into housng grooves. Specifically, the present oil pressure transducer utilizes a retaining ring with a generally V-shaped cross sectional configuration. The V-shaped legs of the retainer cooperate with aligned circumferential grooves, one formed along the outer diameter surface of the inner housing and the other formed along an inner diameter surface of the outer housing. The V-shaped retainer may be conveniently inserted through a small radial space between housing members. This causes the legs of the "V" to flex inward toward one another as the fastener slips into the radial space between the housings. When the V-shaped retainer fully enters the radial space, the leg portions of the "V" expand radially to engage axially facing shoulder portions formed by the aforementioned channels. Thus, the housings and the V-shaped retainer is prevented from relative axial movement.
Previous oil pressure transducers have utilized a base housing portion including a threaded male end portion adapted to be received in a threaded aperture of the engine which fluidly communicates with the lubrication system of the engine. The prior transducers have utilized housing bases with relatively thick walls made by turning and cutting a solid metal cylinder on a screw machine or the like. This produces a relatively thick walled and heavy part. Obviously, another disadvantage of this type of housing is the high cost in machining the housing on the aforementioned screw machine. It has been found that a base housing can be easily formed without machining and with thin walls by cold forming. However, this type of housing lacks a relatively thick wall or a large diameter circumferential surface such as a hexagonal surface which can be utilized to rotate the transducer by a wrench or the like. The subject application describes a housing with a thin walled portion and with a desirable circumferential surface formed thereon defining a wrenching portion. The wrenching portion is formed by a molded elastomeric material or the like and has desirable wrenching surfaces formed thereon. The wrenching portion may be manufactured separately and subsequently joined to the housing by a press fit or by adhesives or the wrenching portion may be mold formed about the base housing.
Therefore, an object of the present invention is to provide an oil pressure transducer having two housing portions joined together with a diaphragm member secured therebetween, the housing portions being axially secured together by means of an annular retaining means which may be inserted into a small radial space between overlapping portions of the two housings and subsequently extends into circumferentially extending grooves in the housing portions.
Another object and feature of the subject transducer is the provision of two housing portions which are axially retained to each other by fastener means insertable between overlying and slightly spaced wall portions, the fastener being a V-shaped annular member with inner and outer leg portions, the leg portions of which are flexible radially inward as the fastener is inserted between the housings and which, subsequently, expand radially in the opposite direction into grooves formed in the housing portions so as to capture the housing portions in desired axial overlapping relationship to one another.
Other advantageous features of the subject transducer will be more readily apparent from a reading of the following Detailed Description of a Preferred Embodiment, reference being had to the accompanying drawings in which preferred embodiments are illustrated.